US1758769A - Multicolor cinematograph and other film - Google Patents

Description

May 13, 1930. J. E. THORNTON 1,758,769

MULTICOLOR CINEMATOGRAPH AND OTHER FILM Original Filed May 5, 1924 2 Sheets-Sheet l Immmzf@ M2111 ey.,

May 13, 1930. .,J. E. THORNTON 1,758,769

MULT-ICoLoR CINEMATOGRAPH AND OTHER FILM Original Filed May 5, 1924 Sheets-Sheet 2 Mayes Ffm/w Affe/1mm". l

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/fzzayes Par/sof/maje Fatented May 13, 1930 narran srarrfas 'igssase @PRICE MULTICOLOR CINEMATOGRAPH AND OTHER lim @riginal application Applications for this invention were tiled in Great Britain May 18, 1923, and Feb. 15, 1924.

rlhis case is a division of Serial No. 711,254

tiled May 5, 1924.

This invention provides a new system, method vor process for the Aproduction of multi-color pictures comprising either four or three colors, in the form of continuous ciiieinatograph iilms, or any other forms of transparencies, such as lantern-slides, window transparencies, advertisements, thin transfer tissues and the like, by entirely photographic methods.

The invention is designed to enable the completed pictures to be produced as double width transparencies comprising two halfpictures each of which contains only two colors, formed upon two lms or plates, of

so, the multi-color screen type, these two-halfpictures being produced by means of two original negatives also in the form of two half-pictures of screen-type and two intermediate printing-clichs also consisting of two half-pictures of screen-type.

This result is attained by the use in coinbination of several factors, including 2-the special method of producing the negatives, which consists in the use in combination of 3o the following elements (l) acamera, one lens, and a light-spliting device which lwill divide the image formed by the lens into two images oi identical size; 2) a special form of sensitive material of double-picture-area to receive these two images, the sensitized material having a pair of adjacent colorscreens or filters (each comprising two colors,

the colors of one screen being diii'erent fromA the colors of the other screen), the lens and 4o light-splitting device dividing the original.

' image into two and the color-screens of the sensitized material making a further division by which the analysis o four or three colors are recorded upon the one sensitive material of double-picturey-area; and (3) by producing a further record or printing clich,'in which the primary images of the original negatives are converted int-o positive images ofthe printing-clich either by chemical reversal or by copying.

led May 5, 1924, Serial No. 711,254, and in Great Britain EIay 18, 1923. Divided. and this application led November 3,. 1925.

Serial No. 66,802.

Reconstruction of the split image and its colors is effected by a double-area positive print, made from the double-area printingclich upon a sensitized material of similar type and also double-area whereon two adjacent positives or half-pictures'are formed,

each comprising two colors, and each with a diiierent pair of colors from the other.

Uompmz'son with previous color systems transfer tissues, and continuous cinemato-A graph films. U

"l`he basis ,of the invention consists in dividing thepictureduring the process of its production into two component parts each part having a dierent color-screen or filter, by doubling the area of the sensitive material, both for the negatives and positives, s o that the two screens are formed in two pictureareas and thus four colors are filtered.

Therefore the improved results attained by thisinvention are accomplished :-(1) partly lby use of the doubleareak sensitive material comprising two screens of two colors and (2) partly by use of the optical system which enables two images of identical size and stand- .point to be formed upon the double-area sensitive-material; and by these joint means to secure four color analysis within the space of two picture areas.

Incidentally the same methods are used to produce three-color pictures if they .are de' sired, by using film-material with its two screens modified in their colorings as hereinafter described.

To the photographer, this invention presents no new points to be overcome, and only requires the substitution of a double-area camera to take the double-area screen film material of the special construction hereinbut double-area sensitive material of the special construction hereinafter described is used instead of ordinary sensitive material.'

In the drawings Fig. 1 is a plan view of a portion of a double width strip of transparent support upon which are formed two screen filters, each of Such filters comprising two colors formed of interspersed fine lines of different colors'.

Fig. 2 isa view similar to Fig. 1 but with screens which will analyze only three colors.

Fig. 3 is a view similar to Iig. 1 wherein the screens are shown as formed of grains.

Fig. 4 is a view similar to F ig. 2 wherein the screens are shown as formed of grains.

Fig. 5 is a view similar to Fig. 1 wherein certainof the screen elements are shown as formed of dots.

Fig. 6 is a view similar to Fig. 2 wherein certain ofthe screen elements are shown as formed of dots.

Fig 7 is a transverse section of a double width screen film negative material comprising a thick Celluloid support, a substratum layer, and a pair of two-color filters, and bearing a pair of black silver primary images of negative character. 'l

Fig. 8 is a transverse section ofa double width screen film positive material 'bearin a pair of secondary images.

Fig. 9 is a transverse section of a double width screen film positive material comprising a celluloid support, a substratum layer, and a pair of two-color filters, and bearing a pair of black silver images of-negative character which serve to block out all the parts of the screens not required as parts of the images.

Fig. 10 is a plan view of a piece of double width film bearing a conventional design.

In all the above drawings the lines and dots are shown very coarse and wide apart for clearness of illustration, but in practice are exceedingly fine, about 500 to the inch and grains finer still.

The ninvention applied to cinematography,

' As the operations are the same for small non-cinematograph pictures and for cinematograph pictures upon continuous lengths of film and as the invention will doubtless be used to a much greater extent for the latter form of pictures, the following description the lines being preferably Structure of the negative material The following is a brief and general description of the negative film-material, a

more detailed description of the material and method of its manufacture being given in the pending application Serial No. 711,254, filed May 5, 1924.

The special film-material upon which the vnegatives are photographed is of the class known as screen film. By this is meant that the transparent Celluloid base is provided with two color-filters (Figures 1 to 6) in the form of very fine multi-colored screens printed or formed upon a substratum amalgamat- `ed upon the face of the Celluloid (oralternatively they may be printed direct upon the celluloid itself), and these screens are afterwards covei'ed with a high-speed panchromatic gelatino-silver-bromide emulsion.

The base used for the negative film (Fig. 7) is preferably of the full standard thickness (about .0045 inch) ,4 and when the substratum, screen, and sensitized layers are added the total thickness of thel negative film is about .0065 inch. A.

Exposure of this negative film in the camera is made with thel transparent base of Celluloid or other material facing towards the lens and thc sensitized side turned away from the lens, so that light passes first through the transparent base (Figure 7), then through the multi-color light-filter, and finally reaches the panchiomatic emulsion, upon which it forms a pair of section-images, each image representing two different color-sensations according to the color of the light which the filter has allowed to pass, and the two images representing four or three such colorsensations."

For four-color negatives The filter-screen for four-color consists of an immense number of exceedingly fine colored dots, lines or mosaic pattern 3 and`5) These are arranged in two groups, side-by-side upon the two halves of the double-widths film strip. One section consists of dots (Figure 5), lines (Figure l) or mosaic pattern (Figure 3) of two colors r (Figs. 1,

lili) llO Each half of the double-width film therefore contains its own complementary color, and the two halves are also complementary to cach other.

For three-color negatives rlhe` filter-screen for three-color is of .a similar character consisting of fine dots, lines, or mosaic pattern, but the colors comprise only crimson-red, blue-green, and blue-violet (Figure 2) and are therefore only semi-complement-ary. rifhey are arranged in two groups, one upon each half of the doublewidth film as in the preceding example, but one of the colors is repeated upon each half. For example one half-width may have a filter-screen ofl red and green, and the other a filter-screen of blue-violet and green. 0r any other preferred arrangements of the combination may be used; for instance by duplicating'the yellow filters on the negative the complementary color, blue-green, will predominate in the positive because it will be duplicated upon 'both halves (Figures 4 and 6) Producing the original (camera) 'negatives The sources of many of the difficulties which occur in the later stages of making the print itself in some other systems of color cinematography are found at the very commencement of operations, viz at the camera and optical section,and in the present invenvresults it is necessary to have four sectionnegatives, each representative of a different color sensation; and for three-color results three section-negatives are necessary.

To secure perfect results all section-negatives must be made by simultaneous exposures at the same moment, in order to secure in each the same identical phase of the subject-movement for each section-picture.

They must therefore all be exposed by means of only one lens in order to secure the same view point.

Photographing 1 each section-picture one after the other in alternating arrangement, as proposed in some systems, shows imagemovement between the section-negatives of every picture, and this is again reproducedin the positive picture, resulting when the picture -is projected on the screen in the serious' image-displacement technically known as fringing. Photographing the sections simultaneously by means of two or more ad] accnt lenses, as proposed in some systems, pro- A duces the alternative objection of image-displacement due to parallax.

It. has therefore been sought by man investigators' to cure all these faults by p otographing through one lens, and then splitting the light of the primary image so that it forms two or more section-images by means of prisms, mirrors, partial reflectors, grids, or the like. These methods are all more or less feasible or satisfactory for producing twocolor pictures, as the primary image has to be only once split to form two section-images;

but when the primary has to be divided into three in order to produce three section-images the optical difficulties are greatly increased, and the cost, bulk, and complexity of the optical devices are very much increased; but when films ofl single-width; or alternatively if the section-pictures were taken on ordinary films of single width two films with a double-tier of two pictures upon each would be required, or a single film with a quad-tier of four pictures. If only a three-color picture is desired objections of a similar nature arise.

To produce either four or three color-section negatives splitting the light is preferable to the image-displacement which results from two successive exposure movements.

By the present invention all these several objections are overcome and it becomes almost as simple to produce cinematograph pictures of four colors as it was formerly to produce pictures of only two colors. The four-color analysis in the negative is secured py using a particular combination, as folows Uombz'mztz'on for producing four-color negatives. At one camera-empoawre The necessary elements of this combination comprise the following:-

(l) A double-width strip of negative film; with a two-color filter-screen of dot, line or mosaic pattern (Figures 1, 3 and 5) in colors such as crimson-red and blue-green, formed upon one half of the double film, and another similar two-color lter-screen such as blueviolet and orange-yellow, formed upon the other half of the double film; the Celluloid side of the film being turned towards the lens, and the light passing through the two screens on to the panchromatic sensitive layer placed furthest from the lens (Figure 7) (2) One exposure-lens; and

(3) One light-splitting prism, mirror, or equivalent optical device, dividing the original image into two and passing the resulting two ima e-beams through the two filtersoreens o the two film-sections, and forming at the focal plane two images of identical size.

By this means four negative section-images in the form of two half-pictures are formed by one lens, from one view point, at one instant, by one exposure, upon one double-picture-area of one negative-film strip.

Producing the printing-clichs Having made the camera exposure and obtained the original negative-records by the method described, it is now necessary to produce a printing-clich from which the final positive-records for exhibition can be printed. At this stage therefore either of the following alternative courses are open (A) The original (camera) negative (which is complementary in its coloring to the actual scene photographed) may be used to produce a corrected positive by printing from the original negative through a lens on to a positive film of similar character, also provided with similar color filters and panchromatic emulsion, in which case the colors on the resulting positive will be again reversed and therefore will be the same as vthose in the original scene or object (Figure 8) (B) The original (camera) negative may be treated by theusual reversal baths and treatment by which it can be converted from a negative of incorrect or complementary 1 colors into a positive of correct or non-complementary colors, `so that the real coloring of the scene or object is produced on thel original film.

(C) A positive in black and White can be reproduced from the colored negative A, or a negative in black and white can be reproduced from the coloredy positive B, by copying through a lens and camera.

" Preferred form of printing-clichs Of these several methods it is preferred in commercial manufacture not to use the original (camera) negative, because of the labor involved in treating continuous lengths of film to the processes of reversal, and also because of the danger of damaging the origi inal negative in the processes.

It is therefore preferred to make a reproduction from the original (Figure 8), and further because by making such reproduction the necessary reversal of image is simulta-l neously effected. Therefore a positive print is made from the original negative by copying in a camera through a lens and developing the .image in the usual way, in accordance with method` A. This will produce acopy in which the black-silver images will be of positive character, and this copy-is used as the printing-clich from which the actual exhibition positives (Figure 9) are reproduced.

Therefore in ltheir final reproductions for exhibition purposes (produced according to `the co-pending application Serial No. 711,254 hereinbefore referred to) the black-silver images will be of negative character and the color-screens visible through them willbe of positive character.

Producing the color positives Having described the methods of producing the original negatives which constitute the primary images, and the printing-clichs which constitute the secondary images, it now only remains to describe the production of the final positives for exhibition, or third images.

Film-material for color-positives But for cinematograph positives the filmg material is made of double standard width (Fig. 9).

Otherwise the positive film-material is similar to that used for the original negatives and intermediate printing-clichs; but the speed of the sensitive emulsion may be slower and its grain therefore finer.

Printing the color positives In the present process each pair of differ- Ordinary non-cinematograph positives ofential positive images is printed in one layer of non-colored sensitive silver-emulsion, behind a screen of colored lines, dots, or other pattern which are visible by transmitted light only to the extent allowed by the silver image,

which formsla mask or cut-out fo I. portions of the coloring and allows the remainder to pass lthrough and constitute the positive picture (Figure l1).

The positive process used in this invention 4is therefore quite different from the processes heretofore used. In the present invention all the images are lof black-silver in the form of black and white transparencies, superimposed,

upon colored screens which cover the whole of the base of the film or plate. y

Vhat I claim asmy invention and desire of the base of the film or p1ate.

l. A method of producing a photograph in the form ofva.; multi-color transparency which consists in photographically splitting the original scene or picture 'into two com ponent half-pictures in two mosaic-colormesma 'picture-area, each half-picture image represcnting a different pair of colors from the other, and photograpliically reproducing from the half-pictures of negative character a further two half-pictures, but ofpositive character, upon another transparent support also of double-picture-area having a sensitized pancliromatic emulsion layer attached to the support and two mosaic-color-screens formed side-by-side upon the support between it and the emulsion thereon, one screenrepresenting and filtering one pair' of colors and the other screen a different pair of colors.

2. A method of producing a photograph in the form of a multi-color transparency which consists in photographically splitting the original scene or-picture into two conipoiient half-pictures in two mosaic-colorscreen images of negative character upon a transparent vsensitized support of doublepicture-area, each halfpicture image representing a different pair of colors from the other, by photograpliically producing two images of identical size and negative character upon the one sensitized support of double-area and by passing the light rays of such images through a pair of mosaic-colormy hand ilar sensitive mosaic-color-screenifilm-material, and finally producing .by projection from the intermediate printing-clichs a pair of iinalv images of positive character upon similar sensitive mosaic-color-screen film-niateri al of double-area and having two screens sidc-by-side, a diiferent pair of colors being represented in each positive image.

4. The method of multi-color photography as described in claim 2wherein the pair of color screen negatives, the pair of` intermediate printing-clichs, and the pair of color screen positives are each formed side-by-side upon supports of double width and doublearea.

The method of producing a multi-color transparency which consists in photographing through a single lens and prism, split ting the picture into two arts on to a sensitive paiiclironiatic screen lm to form two halfpicture negatives, and printing from suc h negatives on to a sensitive panchromatic screen film toproduce two half-picture positives of two colors each. In testimony whereof J'oHN EDWARD THoaN'roN.

screens formed between the double-area suprt and a sensitive panchromatic emulsion layer attached to the support, one screen representing and filtering the other screen a diierent pair of colors,

'thus producing four analyses of color within twopicture areas upon the one support of double area, photographically reproducing from these two half-pictures two intermediate half-pictures in the 'form of printingclichs, also of negative character, upon the `double-area transparent sensitive screen-{ilmmaterial, photographically reproducing from the two printing-clichs of negative character a further two half-pictures, but of positive character, also upon a tra arent sup-` port of double-picture-area,- Vand y printi from the printing-clichs on to the sensit positive support, such double-area support having a sensitized panchromatic emulsion layer attached to the sup rt and two mosaiccolor-screens formed Vsi e-by-side upon the one pair of colors and l support between emulsion and support, one i producing a pair-oflprimaryiinag'es ofintermediate screen representing and. filtering one pair of 1 colors and the other screen a different pair of colors.

'3. A method oproducing a multi-colored transparent photograph which comprises tive character upon a sensitive mosaici-colorscreen film-material of double-width with two screens side-by-sideeachecontaining two colors, one pair of colors being different from the other pair, producing therefrom a l. air

printing-clich secon images also of negative character, uponsin-- of nega-

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